Hand tool for crimping electrical connectors



A ril 17, 1962 w. R. OVER ETAL HAND TOOL FOR CRIMPING ELECTRICAL CONNECTORS 2 Sheets-Sheet 1 Filed Dec. 3, 1959 INVENTOR. HOUHRD E."$T|NE UR. y QMLUHM R- OVER April 17, 1962 w. R. OVER ETAL 3,029,670

HAND TOOL FOR CRIMPING ELECTRICAL CONNECTORS Filed D80. 3, 1959 2 Sheets-Sheet 2 INVENTOR. HOUHRD E. STINE JR. BY wuupm R. OVER m wew 3,029,670 HAND TOOL FOR CRIMPING ELECTRICAL CONNECTORS William R. ver, Union Deposit, and Howard E. Stine,

Jr Harrisburg, Pa., assignors toAMP Incorporated,

Harrisburg, Pa.

Filed Dec. 3, 1959, Ser. No. 857,057

3 Claims. (Cl. 81-15) The process of joining electrical connectors of the ferrule type onto wires by crimping the wire and connector together between a pair of dies requires the development of a very high thrust at the completion of the cycle. During the initial portion of the operation, very little thrust is required and a large die travel is desirable. As the ferrule begins to compress onto the wire, the resistance increases so that it is expedient to increase the generation of thrust accordingly.

It is an object of this invention to provide a hand tool for crimping electrical connectors onto conductors wherein the linkage is so constructed to increase the thrust as the dies move closer together in response to closing of the handle. It is'also an object of this invention to provide such a tool incorporating a linkage having a variable mechanical advantage. The linkage may be designed so that the pressure output of the tool varies with the change of resistance to deformation of the particular application.

Also, it is an object of this invention to provide a compact crimping tool having a linkage with changeable mechanical advantage developing a high thrust at the completion of the stroke.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying itin practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

FIGURE 1 illustrates a tool in closed position embodying principles of this invention;

FIGURE 2 illustrates a tool similar to FIGURE 1 in the open position;

FIGURE 3 is a fragmentary view of the pivoted handle including the cam mechanism and illustrating typical dimensions.

As shown in FIGURE 1, the tool consists of a head member generally C-shaped and a body member 11, having a first dependent handle 12 which may be integral therewith. The upper portion of the bight of the C- shaped frame contains a fixed die 14. This die may be secured in place by any standard securing mechanism. An aperture 16 in the O-shaped frame coaxial with the head and parallel to the handle 12 permits a die holder 18 to slide therein. A second die 20 is secured to the end of the rod 18 nearest the first die 14. Thus, longitudinal movement of the rod 18 causes the dies 14 and 20 to come into engagement or separate depending on the direction of travel. The opposite end of the rod 18 has a clevis 21 which is threaded into the rod 18 capable of adjustment. A pivot pin 22 is inserted into the clevis and permits a link 24 to be pivoted thereto. Another pivot pin 26 in the body member 11 secures a second handle 28 in pivotal relationship to the head and fixed spasms Patented Apr. 17, 1962 handle 12. A cam surface 30 projects from the pivoted handle 28 toward the fixed handle 12.

As shown in FIGURE 2, another pivot pin 32 is inserted into the body member 11 in the vicinity of the fixed handle and has a link 34 secured thereto. The link 24 has one end pivoted intermediately of the link 34 by pivot pin 38, with the opposite end of the link 24- pivoted at the pin 22 to form a toggle-type linkage. A roller member is journalled about the free end of the link 34.

A spring means 42 extends between the fixed handle 12 and the link 34 to urge the tool into open position as seen in FIGURE 2. An adjustable ratchet mechanism, designated R, (e.g., US. Patent 2,618,993) compels the operator to make a complete crimp before the dies can be re-opened. Stop means 44 projecting from the inside of the head 10 abuts against the movable handle 28 when the handle is in full-open position. It is noted that this stop means is threaded for adjustability.

In operation, a connector is placed between the dies when the dies are full-open and a wire inserted into the connector. The handles are then squeezed. to bring them together, driving the lower die 26 toward the upper die via links 34, 24, etc., so that they cooperate to crimp the connector and wire together. Initially before the dies contact the barrel of the connector, the die 2% slides freely so that there is no resistance, other than frictional resistance. In this stage of the stroke, it is desirable to have the maximum die travel per increment of movement of the movable handle. This is accomplished by linkage mechanism having a variable mechanical advantage which is the resultant of: 1) the path of the roller 40 on the bearing surface of the curved cam 39; (2) the angle of the toggle linkage; and (3) the ratio of handle length to the distance between the pins 4t) and 26. The characteristics of the linkage in this operative portion of the stroke provides a substantial vertical component to cause the movable die 18 to move upwardly with a low mechanical advantage, high travel, high speed, closing stroke. The action of the handles thus operates to permit maximum travel of the die with minimum movement of the handle.

As the die approaches the ferrule, continued movement causes a bending of the ferrule to deform it to a position wherein the inside of the ferrule touches the outside of the conductor. During this stage, there is, of course, more resistance than the initial take-up stage, but less resistance than the final crimping stage. This op eration is facilitated by the linkage characteristics which provide an increase in mechanical advantage per increment of die travel. This is eifected by a decrease between the angle of the link 24 and the axis of the free die 18, as well as decreased distance between the pins 40 and 26 which increases the mechanical advantage ratio. As the connector and the wire are deformed together to compress them into a unitary mass, the resistance to die travel continues to increase. The linkage output is continuously readjusted to increase the mechanical advantage per distance of die travel. This provides for the high mechanical advantage, maximum thrust, low travel of the die compared to the handle. The face of the cam 30 is designed so that the surfaces blend smoothly to form a curve on the inside of the cam surface having force characteristics which operationally follow the resistance curve of the connector and the wire. The dimensions shown in FIGURE 3 illustrate the preferred cam configuration for crimping a No. 10 A.W.G. wire in a ferrule designed to accept either a No. 10 or No. 12 wire.

After the wire is crimped, the jaws are again opened to permit insertion of the next conductor. The opening of the jaws is accomplished quickly and easily by a reversal of the cycle,

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

We claim:

1. A device for crimping ferrules onto wires including relatively movable dies cooper-able to crimp the ferrule therebetween, linkage means generating a mechanical advantage for operating said dies, and handle means for operating said linkage means, said linkage means comprising a toggle linkage with a roller on the driven end of the toggle and a cam surface on the handle means having an irregular surface cooperable with the roller to operate the toggle linkage. I

2. A connector crimping tool including a head member, 21 first handle secured to said head member, a second handle secured to said head member relatively movable with regard to said first handle, a pair of relatively movable dies in said head member, and means for moving said dies including linkage means between the dies and the handle members, saidlinkage comprising a first link pivotally secured at one end to the first handle and having a roller member on the opposite end, a second link pivot ally secured to one of said relatively movable dies at one end and at the other end pivotally secured to an intermediate portion of the first link, and a cam surface on the second handle in engagement with said roller member.

3'. As a sub-combination in a connector crimping tool comprised of a pair of handles which drive a die means,

said tool having a mechanical advantage varying linkage. including a link pivoted to one handle at one end and having a roller at the opposite end, a cam surface on said other handle engaging said roller member, said cam surface having variable radii of curvature, and a second link pivoted at one end intermediate the ends of the first link, and at the opposite end to the die means, whereby closure of the handles results in a varying mechanical advantage to generate a thrust which increases as the resistance to crimping increases.

References Cited in the file, of this patent UNITED STATES PATENTS 542,035 Willever July 2, 1895 726,013 Aue Apr. 21, 1903 2,339,880 Romanofi Jan. 25, 1944 2,385,835 Neal Oct. 2, 1945 2,861,488 Barnes Nov. 25, 1958 2,892,368 Demler June 30, 1959 FOREIGN PATENTS 138,347 Great Britain June 17, 1920 

